Kanamycin embonate

ABSTRACT

Kanamycin embonate and pharmaceutical preparations thereof, useful as antibiotics, are disclosed. Kanamycin embonate is prepared by reacting a water soluble salt of embonic acid with an aqueous solution of kanamycin or a salt thereof.

United States Patent Guadagnini et al.

KANAMYCIN EMBONATE I Inventors: Giuseppe Guadagnini, Sunnazzaro dei Burgondi; Franco Fabi, Milan,

both of Italy Assignee: Pierrel S.p.A., Milan, Italy Filed: Aug. 7, 1970 Appl. No.: 62,147

Foreign Application Priority Data Aug. 14, 1969 Great Britain ..40,754/69 US. Cl. ..260/2l0 K, 424/180 Int. Cl. ..C07g 11/00 Field of Search ..260/2l0 K 51 Sept. 12, 1972 56 References Cited UNITED STATES PATENTS 2,931,798 4/1960 Umezawa et al ..260/2l0 K 3,156,617 ll/l964 Granatek et al. ..260/2l0 K Primary Examiner-Lewis Gotts Assistant Examiner-Johnnie R. Brown Attorney-Bacon and Thomas [57] ABSTRACT 1 Claim, No Drawings tibiotics", Series A, 11, 120-121 (1958) to have the following formula:

(Emmi; CHzOI-I l on I I IhN no o i 1 on on on lIgN- -Nll- Kanamycin can be seen from the above formula to have four free amino groups per molecule and it may form acid addition salts with many acids. Kanamycin is ordinarily recovered from its fermentation broths and produced commerciallyin the form of its monosulphate.

Kanamycin embonate,i s a bacteriostatic substance, which has similar antibiotic properties to kanamycin, being effective against both Gram positive and Gram negative bacteria.

Kanamycin embonate is also less toxic and less water soluble than kanamycin itself and furthermore it is particularly effective in the treatment of intestinal diseases.

An important requirement for a product to be therapeutically active in the treatment of intestinal diseases, particularly of diarrheic ones, is that it should be possible to maintain a high concentration of active substance in'contact with the'affected part, substantially without absorption of the compound. [t is also important that the pharmaceutical composition containing the active compound should have a high adsorbing tained in contact with the affected surface for a longer period of time. The salt also possesses a high adsorbing power, superior in fact to that of vegetable charcoal as shown when the two substances are compared using methylene blue solutions buffered to pH 7.4. Theab. sorbingvpower of kanamycin embonate with regardto bacterial cultures is also superior to that ofkaolin as shown in thefollowing test: Two bacterial cultures, the first one of Salmonella tiphimuriumwhich is sensitive to] kanamycin, and the second one. of Aerobacter aerogenes which is resistant to kanamycin, are incubated for 18 hours and then kanamycin embonateand kaolin respectively are added in amounts of 20 mg./ml. each. The the resulting suspensions are shook for 30', left to stand for 3 hours and finally aliquots of the supernatants are collected and diluted with physiologic solution.

The bacterial counts have been carried out by means of two techniques for each case showing the results reported in the table here'below. With the first technique, the diluted solution has been used for inoculating Petri dishes containing trypticase-soy-agar and the number of viable bacterial cells calculated- With the second technique, the total number of bacterial cells (viable and dead) has been calculated using a Burker apparatus.

Petri Dishes Burker lni- Bac. Dif. tial Bac. ct. Difs. lnict. of bactafter of bac. 1 tial after bac. erial treatcounts bac. treatcount 'count ment in count ment in Kanamycin Embonate 1st test: 2.3 2.l l0 99% 3X10 2.95 99% S. liphimurium l0 X10 A .aerogen es l 0" aolin 1st test: 2.3 SXlO" 78.4% 3X10 7.2 76% SJip/limurium X10 X10" A .aerogenes l 0 X 10 The adsorbing properties of the new salts are combined with the antibiotic characteristics of kanamycin, and it is therefore possible to prepare pharmaceutical compositions that possess the necessary requirements for effective treatment of intestinal infections, without the necessity to add any other substance to the kanamycin embonate.

Kanamycin embonate can easily be prepared by any of the processes suitable for the preparation of salts.

In the process according to the invention a solution of a soluble salt of embonic acid, preferably the sodium or potassium salts, is reacted at room temperature with a solution of a soluble salt of kanamycin, preferably a sulphate.

The molecular ratio between the kanamycin and the embonic acid in the reaction medium should be 1:2 or more than 2. The kanamycin embonate precipitates and is separated by filtration and washed with water to remove the sulphate ions. The kanamycin embonate has the following characteristics:

Molecular weight: I26 I .60 Contents: cmbonic acid 61.6%

kanamycin base 38.4%

Structural formula:

$HQNH2 OHQOH OH 5% i H o l H OH O H NH C O OH I CH2 l:OH

C O OH Physicochemical characteristics:

Microcrystalline yellow powder Melting point (with decomposition): about 225C Practically insoluble in:

water, acetone, benzene, chlorform, diethylamine,

isopropylalcohol, methylene chloride, pyridine, carbon tetrachloride Sparingly soluble in:

methyl and ethyl alcohols.

Soluble in:

Dimethylsulphoxyde, dimethylformamide, alkalies.

Antibiotic spectrum: The antibiotic of spectrum of kanamycin embonate does not substantially differ from that of kanamycin sulphate. In the following table we are reporting the data relative to the minimum inhibiting concentration of the two salts in comparison with various bacterial and fungal species. The minimum inhibiting concentration is given in 'y/ml. and it is expressed as activity referred to kanamycin base for both salts.

Kanamycin Kanamycin Sulphate Embonate TEST GERMS (m.i.c. in (m.e.c. in

y/ml.) y/ml.)

S. Aureus ATCC 65388 8 l I B. cereus var. mycoides ATCC l I778 l2 l2 5. cerevisiue 9763 I20 I20 E.coliATCCll3/3 (ATCC 11105) 20 20 S. ltaemolilicux 9854 I I 65 S. ryplu'murium ex CllVP 478 4 4 .Slflarus ATCC 10240 l0 12 B. megalherium ATCC 10778 0.3 0.25 B.subli1is ATCC 6633 2 1.5 S. lureu ATCC 9341 8 6 S. mnnei ATCC 9290 24 24 P. mullocida ATCC 12948 24 24 C. albicuns ATCC 1023] I20 I20 .S'ulm. paruliphi A 4 4 Salm. puruliphi B 8 8 Slligella dysenlerial: Shigella flatnen' 10 IO The LD of kanamycin embonate, orally administered (Sprague Dawley) is higher than 5000 mg/Kg. expressed as mg. of base per Kg. of live weight.

ACUTE TOXICITY The acute toxicity was investigated in the mouse and rat by administering orally kanamycin embonate also at the maximum dose level of 5 g./Kg. b.w. (body weight) per day (activity expressed as kanamycin base). No death occurred in 7 days of treatment.

SUB-ACUTE TOXICITY 4 CHRONIC TOXICITY A chronic treatment was investigated in Albino rats of both sexes by administering orally kanamycin embonate at two dose levels: 50 and mg./Kg. b.w. per day (activity expressed as kanamycin base) for days.

The treatment did not affect the following parameters: growth rate, blood N, blood glucose, emopoietic system, bone marrow formation, liver function, kidney function, e.k.c., weight gain and gross histological examination.

A chronic treatment was investigated in adult dogs by administering orally kanamycin embonate at two dose levels: 83 and 166 mg./ Kg. b.w. per day (activity expressed as kanamycin base), for 180 days. The treatment did not affect the following parameters: weight gain, blood N, blood glucose, emopoietic system, bone marrow formation, kidney function, serum glutamic oxalacetic transaminase, serum glutamic piruvic transaminase, serum alkaline phosphatase, and gross histological examination of the main organs.

EMBRYOTOXICITY The embryotoxicity was investigated in rats and rabbits by administering orally kanamycin embonate at the maximum dose of 166 mg./Kg. b.w. per day (activity expressed as kanamycin base) from the 3rd to the 17th day of pregnancy inclusive.

The treatment did not affect the gestation and showed no noxious effect on the pregnant animals and on the embryo-fetal development.

OTOTOXICITY The ototoxicity was investigated by administering orally kanamycin embonate in Guinea pigs at the dose of I00 mg./kg. b.w. (activity expressed as kanamycin base).

The treatment produced no significative modification of the cochliovestibular function and of the histological structure of the interior ear.

ABSORPTION Kanamycin embonate administered orally is slightly absorbed by the gastroenteric walls and it can be absorbed only at very high dosage levels, however its absorption is always inferior than the absorption of equal dosage of kanamycin sulphate.

EXAMPLE OF PREPARATION:

A solution of 86.6 g. (0.2 moles) of sodium embonate in 2 l. of water is slowly added under stirring at room temperature, to a solution of 67.8 g. (0.1 mole) of kanamycin disulphate dissolved in 2 l. of water. A light yellow precipitate is formed, which is then filtered, washed with water and dried under vacuum.

One-hundred and twelve g. of kanamycin embonate, having the above reported characteristics and having an activity of kanamycin: 330 3 80 U/mg. are obtained.

The pharmaceutical compositions in liquid forms suspensions, syrups, drops contain from 0.5 g. of kanamycin embonate per ml. depending from the particular formulation, together with suitable sweetening, flavoring, thickening or dispersing agents. For veterinary purposes,, kanamycin embonate is administered orally in form of extemporary suspension or tablets at dosages depending from the kind of animals to be treated.

What we claim is:

l. Kanamycin Embonate. 

